Cytoreductive Surgery and Intraperitoneal Chemotherapy in Patients with Peritoneal Metastases from Colorectal Cancer: Aspects of loco-regional treatment outcome, patient selection, and chemo-sensitivity

“Never mistake knowledge for wisdom.

One helps you make a living; the other helps you make a life.”

-Sandra Carey

In honour of God and to my loving wife, Helena, and our children…

List of Papers

This thesis is based on the following papers, which are referred to in the text by their Roman numerals.

I Cashin PH, Graf W, Nygren P, Mahteme H. Treatment Out- come and Tumour Recurrences after Cytoreductive Surgery and Intraperitoneal Chemotherapy in Patients with Colorectal Peri- toneal Carcinomatosis. Eur J Surg Oncol. E-publish April 2

. 2012. DOI:10.1016/j.ejso.2012.03.001

II Cashin, PH., Graf, W., Nygren P., Mahteme H. Patient Selec- tion for Cytoreductive Surgery in Colorectal Peritoneal Carci- nomatosis using Serum Tumour Markers – an Observational Cohort Study. Accepted Annals of Surgery

III Cashin PH, Graf W, Nygren P, Mahteme H. Intraoperative Hy- perthermic or Postoperative Normothermic Intraperitoneal Chemotherapy for Peritoneal Carcinomatosis from Colon Can- cer: A Case-Control Study. Ann Oncol. 2012; 23:647-52.

IV Cashin PH, Mahteme H, Graf W, Karlsson H, Larsson R, Ny- gren P. Activity ex vivo of cytotoxic drugs in patient samples of peritoneal carcinomatosis with special focus on colorectal can- cer. Manuscript.

Reprints were made with permission from the respective publishers.

Contents

Introduction...11

2 Background...13

2.1 Peritoneal metastasis ...13

Defining peritoneal surface malignancy ...13

The anatomy of the peritoneum...13

The treatment history of peritoneal metastases...14

The development of modern intraperitoneal chemotherapy ...15

The development of modern surgical treatment of PM ...16

2.2 Colorectal cancer...17

Overview of colorectal cancer pathogenesis ...17

The treatment of metastatic colorectal cancer ...17

2.3 Cytoreductive Surgery...18

The technique ...18

Surgical scores...19

2.4 Intraperitoneal chemotherapy...20

The rationale for intraperitoneal chemotherapy...20

Early postoperative intraperitoneal chemotherapy ...20

Sequential postoperative intraperitoneal chemotherapy ...21

Hyperthermic intraperitoneal chemotherapy (HIPEC) ...21

Chemo-sensitivity testing ...22

2.5 The premises of the thesis ...23

Current research problems in the area of colorectal PM...24

3 Aims of the thesis...26

Specific aims: ...26

4 Common methods ...27

Ethical considerations...27

The CRS and IPC database and eligibility requirements...27

The SPIC procedure...27

The HIPEC procedure...27

General Statistics ...28

5 Summary of Papers ...29

5.1 CRS and IPC treatment of colorectal PM ...29

Patients and methods ...29

Results ...30

Discussion...34

5.2 Patient selection for CRS and IPC ...36

Patients and methods ...36

Results ...38

Discussion...41

5.3 Intraoperative HIPEC vs. postoperative SPIC...43

Patients and methods ...43

Results ...45

Discussion...47

5.4 Chemo-sensitivity profiles in PM...49

Materials and methods...49

Results ...51

Discussion...54

6 General discussion ...58

Outcome analysis...58

Patient selection...60

Intraperitoneal chemotherapy: methodology and chemo-sensitivity...61

6.1 Conclusions ...62

7 Svensk sammanfattning ...63

7.1 Bakgrund ...63

7.2 Kort sammanfattning av delarbeten ...64

Delarbete I - överlevnadsanalys...64

Delarbete II - patientselektion ...65

Delarbete III – Metod för intraperitoneal cytostatika ...65

Delarbete IV – Kemosensitivitet och val av cytostatika...66

7.3 Slutsatser ...66

8 Acknowledgements...67

9 References...69

Abbreviations

5-FU AML AUC CC score CI CLL C

Corep CRC CRS DFS EPIC FDA FMCA HIPEC IC

IP IPC IV N/A MMC MNC OS PM PMP PCI PSS SI SPIC STMs TTP

5-fluorouracil

Acute myeloblastic leukaemia

Area under the curve (concentration time) Completeness of cytoreduction score Confidence interval

Chronic lymphocytic leukaemia Maximum concentration

Colorectal Peritoneal Carcinomatosis (score) Colorectal cancer

Cytoreductive surgery Disease free survival

Early postoperative intraperitoneal chemotherapy Fluorescein diacetate

Fluorometric microculture cytotoxicity assay Hyperthermic intraperitoneal chemotherapy Survival index of 50%

Intraperitoneal(ly)

Intraperitoneal chemotherapy Intravenous(ly)

Not available or not applicable Mitomycin C

Mononuclear Cell Overall survival Peritoneal metastases Pseudomyxoma peritonei Peritoneal cancer index Prior surgical score Survival index

Sequential postoperative intraperitoneal chemotherapy Serum tumour markers

Time to progression

Introduction

Colorectal cancer is the third most common cancer in the world for men, with 663,000 new cases each year (10% of all cancers)

. It is the second most common cancer for women with 571,000 new cases each year (9.4% of cancers)

. As such, it is a disease with great implications on a global level. In Sweden, its prevalence has been increasing since the 1970s; fortunately, mortality in this disease has been decreasing over the same time period

.

While there are good epidemiological registries for colorectal cancer, mortality and prevalence figures for colorectal cancer with peritoneal metas- tases (PM) are scarce. There are now three large population-based studies investigating the prevalence of colorectal PM

. The results are detailed in the table. Approximately 2.7% of all colorectal cancer have isolated syn- chronous PM at the time of diagnosis. These patients are potential candidates for cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC).

Only one of these studies (Segelman et al.) reports epidemiological data on metachronous PM from colorectal cancer. One may expect another 1.6%

from the total population of colorectal cancer. This results in an estimated 4.3% of colorectal cancer cases that could be potential candidates for CRS and IPC treatment. In Sweden, where the incidence of colorectal cancer is approximately 6,000/year, the number of potential candidates would be ap- proximately 260/year

.

Prevalence of colorectal peritoneal metastases

n=18,738

Jayne et al n=3,019

Segelman et al n=11,124

Summary n=32,881

Synchronous colorectal PM

with systemic metastases without systemic metastases

n (%) 905 (5) 509 (3) 395 (2)

n (%) 214 (7)

89 (3) 125 (4)

n (%) 477 (4) 119 (1) 358 (3)

Mean 4.9%

2.2%

2.7%

Metachronous colorectal PM with systemic metastases without systemic metastases

N/A N/A N/A

135 (4) N/A N/A

447 (4) 270 (2) 177 (2)

4.1%

2.4%

1.6%

Several years ago, colorectal PM was considered a terminal illness and a generalised form of cancer. Patients were offered palliative chemotherapy.

According to Klaver et al’s population-based study (the same patients as in

the prevalence study by Lemmens et al detailed in the table), the median

survival of patients with isolated colorectal PM treated with systemic che-

motherapy has increased slowly from 11 months (1995-2000) to 13 months (2000-2004) to 19 months (2004-2008)

. The four-year overall survival re- ported was still dismal at just above 10% regardless of time-period. Fur- thermore, when including all patients with isolated colorectal PM (even those not receiving systemic chemotherapy), the overall survival had not changed at all over time for this patient group. While systemic chemotherapy may have a short-term effect, few patients are ever cured and the long-term survival remains bleak.

The relatively new treatment option of CRS and IPC for colorectal PM is still under investigation and while some contention remains, its use has grown considerably over the last few years. This thesis intends to further examine this area of research, as several studies have shown a potential for long-term survival and cure in this illness which was previously considered generalised and terminal.

This is a picture of extensive metastatic disease to the right diaphragmatic peritoneum

which has been mobilised from the muscle of the diaphragm. The liver can be seen un-

der the surgeon’s hand in the abdomen. The patient’s head is to the right and legs to the

left of the picture. Picture taken at the Uppsala University Hospital.

2 Background

2.1 Peritoneal metastasis

Defining peritoneal surface malignancy

Peritoneal surface malignancy (peritoneal carcinomatosis) is a malignant disease of the peritoneum and it may be primary or secondary. Primary peri- toneal surface malignancy is a rare form of cancer that originates from the peritoneal tissue, such as mesothelioma. Secondary disease, known as peri- toneal metastases (PM), is a much more common form of peritoneal surface malignancy and occurs when a malignant tumour metastasises to the perito- neal surface. Gastrointestinal and gynaecological malignancies are the most common tumours that will metastasise to the peritoneum. This metastatic form of cancer mainly occurs in two ways. Tumour cells may exfoliate into the peritoneal cavity due to transserosal growth of the primary tumour

or the cells may be dispersed during surgery from transected lymph nodes, blood vessels, or manipulation of the primary tumour

. Haematogenic metastasis to the peritoneum does occur but is uncommon.

The anatomy of the peritoneum

The peritoneum is a serous membrane composed of a layer of mesothelium

with an underlying thin layer of connective tissue (Figure 2.1). It lines the

inside of the abdominal wall (parietal peritoneum) and covers most of the

intra-abdominal organs (visceral peritoneum). There are two main peritoneal

compartments within the abdominal cavity (Figure 2.2) – the greater sac

(general abdominal cavity) and the lesser sac (bursa omentalis). These two

compartments communicate with each other through the foramen of winslow

(foramen epiploicum).

Figure 2.1 – The peritoneum is marked in red. Gray’s Anatomy 1918.

The treatment history of peritoneal metastases

Previously, once cancer had spread to the peritoneum, the disease was con- sidered systemic or generalised with no hope of cure. Treatment was aimed at alleviating symptoms such as malignant ascites, obstruction or pain.

Surgical treatment to alleviate symptoms was only implemented when bowel obstruction occurred and not as a means for cure. During the 1970s and 1980s, debulking surgery started to come into use for tumours that were less malignant and where survival could be prolonged. PM from ovarian cancer

, testicular cancer

and pseudomyxoma peritonei

are three exam- ples of tumours that were sometimes debulked for improved survival.

Chemotherapy treatment of PM has a longer history. A blood/peritoneal

barrier exists where the uptake of intraperitoneal fluid into the bloodstream

is filtered in various ways. Research concerning the blood/peritoneal barrier

goes back as far as 1895

and it has been investigated extensively since then

due to the use of peritoneal dialysis. However, it was not until the 1970s that

pharmacokinetics and intraperitoneal chemotherapy were investigated sys-

tematically with pharmacokinetic models

. Despite this, injections of che-

motherapeutic agents into the peritoneal cavity started during the first half of

the 20

century. The treatment was mainly used for palliating malignant

ascites

. Thio-TEPA was one of the first drugs used in this manner

. Later,

5-fluorouracil (5-FU) was developed and several indications for its use were

established, among them the intraperitoneal chemotherapy (IPC) treatment of malignant ascites. Three to four grams of 5-FU was instilled directly into the abdomen intraperitoneally

.

In the 1950s and 1960s, a new experimental technique was developed where loco-regional chemotherapy was administered in the form of extra- corporeal perfusion treatments

. Around the same time, hyperthermia and hypothermia were investigated for their cell destructive or protective proper- ties

. This resulted in loco-regional perfusion treatments combined with hyperthermia first on dogs

and then on humans

using chemotherapy drugs such as cytotoxan and A139. In contrast to IP injections, these treat- ments were performed by isolating the arterial and venous circulation to the abdomen (primarily using the mesenteric superior artery and vein) and per- fusing through them

. The aim of these treatments was palliation, more spe- cifically the palliation of malignant ascites or pain.

The development of modern intraperitoneal chemotherapy

A renewed interest in loco-regional IPC developed during the 1970s and early 1980s. Based on information from the earlier studies on hyperthermia

Figure 2.2 – The peritoneum covers two cavities within the abdomen, the

greater abdominal cavity (red) and the bursa omentalis (blue). Gray’s

Anatomy,1918.

and extracorporeal perfusion mentioned above, Spratt and colleagues per- formed a canine experiment using an extracorporeal perfusion system with hyperthermia that perfused the peritoneal cavity instead of the arterial and venous perfusions mentioned earlier

. Furthermore, as the penetration of chemotherapy through the peritoneum is limited

, it was recognised that this hyperthermic perfusion should be used in connection with cytoreductive surgery (explained further below) where the macroscopic tumour is resected and the residual microscopic disease can then be treated with the hyperther- mic perfusion

. Since 1980, this hyperthermic perfusion of the intraperito- neal cavity has developed into what is known as HIPEC (hyperthermic in- traperitoneal chemotherapy). Other methods of IPC have been developed over the same time period, and these will be discussed later.

The development of modern surgical treatment of PM

Previously, debulking surgery was not considered a technique for achieving the radical removal of all tumour tissue, but rather as a way to reduce the sheer volume of tumour tissue. However, Paul Sugarbaker at the Washington Cancer Institute, hypothesised that peritoneal surface malignancy could per- haps be thought of as a loco-regional disease that is not generalised or sys- temic. This new paradigm came from the experience that certain types of peritoneal surface malignancies, such as pseudomyxoma peritonei, rarely spread haematogenously. In conjunction with IPC, he proposed that macro- scopic removal of all tumour tissue combined with IPC might be able to cure patients of their PM disease. For this purpose, he developed different peri- tonectomy procedures that were used not just to debulk but to macroscopi- cally remove all visual tumour tissue

. This aggressive form of debulking surgery has now come to be known as cytoreductive surgery (CRS). This form of surgery has also lead to a new understanding of the peritoneum, where it is considered an organ with natural barriers to invasive growth in much the same way as the liver is viewed.

Some of the first publications reporting safety results using the CRS and

HIPEC method came during the late 1980s and early 1990s

. Fujimoto

and colleagues produced the first diagnosis-specific results from gastric can-

cer in 1988

. Closely thereafter, early small-scale feasibility and/or efficacy

studies were published on pseudomyxoma peritonei

, ovarian

, colorectal

,

and malignant mesothelioma

tumours. During the past 10 years, research in

each area has grown and there is now consensus that CRS and HIPEC is the

treatment of choice for pseudomyxoma peritonei

and malignant abdominal

mesothelioma

. Debate is still ongoing, however, concerning the treatment

of colorectal PM with CRS and HIPEC, which is the main focus of this the-

sis.

2.2 Colorectal cancer

Overview of colorectal cancer pathogenesis

Colorectal cancer (CRC) arises due to mutations in the DNA of the epithelial cells in the lining of the colon or rectum. Some mutations may be genetically inherited while most are acquired through various environmental factors. At some point in time, these mutations create conditions that make the uninhibi- ted growth of some cells possible, causing polyps in the epithelial lining of the bowel wall. In time these polyps may gain more genetic alterations that can make them grow invasively and therefore become a malignant can- cer

. CRC has been a part of the human disease panorama for many years.

The oldest histological diagnosis of CRC was made by Zimmerman in an Egyptian mummy of the Ptolemaic period (200-400 BC) with a carcinoma of the rectum

. Early surgical treatments for primary CRC have been published since the end of the 19

century

. Since that time, many improvements in the treatment of colorectal cancer have been developed.

The treatment of metastatic colorectal cancer

Surgical treatment for localised CRC has existed since the end of the 19

century and with chemotherapy (and radiation in rectal tumours) the progno- sis of localised CRC has improved greatly

. However, metastatic CRC still represents a therapeutic challenge. Patients can present in one of two ways.

Either the cancer has spread at the time of diagnosis (synchronous metasta- ses) or it recurs during the follow-up period after the primary treatment (metachronous metastases). There are four main sites for CRC metastases – lymph nodes, liver, lung and peritoneum. There are early reports of the sur- gical treatment of CRC liver metastasis from the 1940s

. Systematic reports became more widespread during the 1960s and 1970s

. Currently, CRC liver metastases are usually considered for surgical treatment sometimes with peri-operative chemotherapy as a part of established healthcare routines in Sweden as in many other countries

. Isolated lung metastases are not as common as liver metastases, but are also treated surgically in many circum- stances

.

CRC with metastases to the peritoneum, colorectal PM, used to have a

notoriously poor prognosis with a median survival of between 4 and 7

months depending on disease extent at diagnosis

. This form of metastasis

was considered terminal and no surgical treatments were offered other than

palliation of bowel obstruction (see section “Treatment history of peritoneal

metastases” above). Until the recent use of CRS and HIPEC for colorectal

PM, the main treatment option for prolonging survival was systemic chemo-

therapy. In two recent small retrospective studies with systemic treatments of

isolated colorectal PM, the median survival was 16.8-23.9 months

. How- ever, the long-term results are still disappointing, with a five-year survival rate of only 6 to 13%. One population-based study of isolated synchronous colorectal PM showed that the median overall survival (2004 -2009) was 19 months with a 4-year survival of around 10%

. This is consistent with the prognosis of advanced colorectal cancer in general with median survival of 17.9-23.9 months and a five-year survival rate of 3-10%

. New research is being published and there is now growing evidence that a shift in treatment for colorectal PM should be made from systemic chemotherapy to CRS and HIPEC. However, the scientific evidence is still somewhat weak and to date there is only one randomised control trial showing improved survival in pa- tients treated with CRS and HIPEC versus systemic chemotherapy alone

. This scarcity underlines the importance of rigorous reporting from those centres performing CRS and HIPEC.

2.3 Cytoreductive Surgery

The technique

As described earlier, CRS is a relatively new development in the surgical treatment of advanced abdominal cancer. The general consensus has been that this technique should only be used in patients with no haematogenic, extra-abdominal or retro-peritoneal lymph node metastases

. Briefly, peri- tonectomy is performed using 200-300W diathermia for maximal tumour destruction

. This technique involves the stripping of only disease-affected peritoneal layers from the abdominal wall, diaphragm, or pelvic walls. This results in several different peritonectomy procedures: right parietal peri- tonectomy (including the right iliac fossa), left parietal peritonectomy (in- cluding the left iliac fossa), right diaphragmatic peritonectomy, left dia- phragmatic peritonectomy, and pelvic peritonectomy. The CRS procedure is most often combined with a total greater omentectomy as tumour nodules are hard to detect in this tissue. If viscera are affected they are removed whenever possible, for example by means of cholecystectomy, splenectomy, hysterectomy, salpingo-oophorectomy, and all forms of hollow organ resec- tions including rectal resections. If the surface of the liver is affected it is vaporised with diathermia. Nodules on the mesenterium, hepatoduodenal ligament, omentum minus, Gerota’s fascia, or bursa omentalis are locally resected or vaporised with diathermia.

The aim of the surgery is to achieve complete macroscopic removal of all

visible diseased tissue. This is sometimes not possible due to disease in-

volvement of visceral organs. The most common failure site is the small

bowel. If too much small bowel is affected then success is not possible with-

out risking short bowel syndrome. Other failure sites are extensive retro- peritoneal growth along the vena cava or aorta, pancreatic growth, deep liver hilum growth, or invasive diaphragmatic or pericardial growth.

Surgical scores

Three different scores are commonly connected with the CRS procedure:

prior surgical score, the peritoneal cancer index, and the completeness of cytoreduction score

. The prior surgical score (PSS) is a measure of the amount of surgical trauma prior to the CRS procedure, described by dividing the abdomen into 9 regions. A score of 0 means no surgical trauma or only biopsy, while 1 means minimal surgery involving 1-2 regions. A score of 2 means dissection has been performed in 3-5 regions of the abdomen and a score of 3 means dissection has been performed in >5 regions. The perito- neal cancer index (PCI) is a semi-quantitative measure of the tumour burden.

The abdomen is divided into 13 regions and each region can have a score of 0 to 3 depending on the lesion size (Figure 2.3). Therefore, the top score is 39. Lesion size 0 means no visible tumour; 1 means nodules up to 0.5cm; 2 means nodules up to 5cm, and 3 means nodules>5 cm. An important aspect of PCI is that it can only be calculated after a full surgical exploration. The completeness of cytoreduction score (CC score) is the surgical result of the CRS. A score of 0 means there is no visible remaining disease. This is also referred to as an R1 resection, which is a macroscopically complete resection but not microscopically complete. A CC score of 1 means there are remain- ing nodules < 0.25cm in size; 2 means between 0.25cm and 2.5 cm, and 3 means remaining nodules > 2.5 cm.

Figure 2.3- This figure details the 13 regions of the peritoneal cancer

index. The figure is an original from Dr. Sugarbaker and is published

with his consent.

2.4 Intraperitoneal chemotherapy

The rationale for intraperitoneal chemotherapy

One main advantage of intraperitoneal chemotherapy (IPC) over intravenous administration is the dose difference that can be achieved. This is possible due to the blood/peritoneal barrier, which regulates the transport of macro- molecules from the peritoneal space to the blood.

This diffusion barrier provides a pharmacokinetic advantage where the area under the curve (AUC) in the peritoneal concentration is much greater than in the resulting plasma concentration. This ratio (AUC peritoneal/AUC plasma) can range from 8 to 1000 depending on the drug.

This makes it possible to administer much higher concentrations IP than intravenously (IV) without an increased risk of systemic toxicity.

A second important advantage with IP administration compared to IV is the chemotherapy penetration of tumour nodules. IPC offers better penetra- tion of the periphery of the tumour nodules where the blood supply is poor

. However, this penetration is limited to 1-2 mm

, highlighting the impor- tance of a successful cytoreduction, as tumour nodules greater than 1-2 mm may not be adequately treated with intraperitoneal chemotherapy alone. Re- cently, the fact that IP and IV administrations can each reach different areas of the tumour nodule has been exploited by employing bidirectional treat- ment approaches where IP and IV administrations are combined.

Lastly, hyperthermia is a unique feature of IPC treatment, specifically the HIPEC method, which is explained further below. Hyperthermia has been tested preclinically both in an in vitro model of cell cultures and in animal studies.

Evidence from these studies suggests that hyperthermia enhances the cytotoxic effects of certain chemotherapeutic drugs. Particularly interest- ing is a 5-arm study with rats conducted by Pelz et al. Hyperthermia alone and chemotherapy alone (mitomycin C) gave similar positive results com- pared to control groups (positive and negative controls), but the combination of chemotherapy and hyperthermia produced a significant synergistic effect with the best results. Hyperthermia is also known to have a certain cytotoxic effect in itself and to reduce tumour interstitial pressure which can enhance the uptake of chemotherapeutic drugs.

So far, no randomised trial has been conducted to prove its clinical efficacy as part of HIPEC treatment in humans. A description of the different IPC treatment methods currently in use is given below.

Early postoperative intraperitoneal chemotherapy

Early postoperative intraperitoneal chemotherapy (EPIC)

is a normother-

mic administration of intraperitoneal chemotherapy given postoperatively. It

is usually given daily directly after surgery for 5 or 6 days and the most

common drug used is 5-FU. EPIC has also been used in combination with hyperthermic intraperitoneal chemotherapy (HIPEC), but this combination is not as common due to the increased risk of postoperative complications, such as enterocutaneous fistulas

.

Sequential postoperative intraperitoneal chemotherapy

Sequential postoperative intraperitoneal chemotherapy (SPIC)

is similar to EPIC in that the first course of treatment is given postoperatively within 7 days. The treatment is then repeated at 4 to 6 week intervals as an adjuvant IPC treatment for 6 months

. The advantage with SPIC is that it is a loco- regional adjuvant treatment of PM, hopefully preventing recurrences in the abdomen. Since all the chemotherapy will be cleared through the blood and then urine, it also functions systemically as a slow drug release mechanism.

As this treatment is similar to systemic treatment, the same choice of drugs applies. For colorectal PM, the primary drug used in SPIC is 5-FU

. This form of IPC has several disadvantages such as problems with catheter mal- function and drug distribution.

Hyperthermic intraperitoneal chemotherapy (HIPEC)

The HIPEC method is very heterogeneous and there is currently no stan- dardisation. Common to all methods are the hyperthermia and the circulating perfusate. No set temperature has been determined. However, due to the difficulty of keeping a totally homogeneous temperature in the abdomen, the most common target temperature is between 40 and 43

C

. Table 2.1 lists the pros and cons of different closure techniques in HIPEC.

The choice of drug for HIPEC treatment of colorectal PM is not currently

standardised. Chemotherapeutic drugs that are suitable for such treatment

should, in theory, be large, water-soluble and ionised compounds, because

they would diffuse slowly across the peritoneum leading to a higher intrap-

eritoneal concentration than in the blood. Furthermore, as the treatment is

rather short and the abdomen is rinsed after HIPEC, cell-cycle independent

drugs are preferable

. There are several drugs in use for CRC. When hyper-

thermia was introduced in HIPEC, cisplatin

and mitomycin C

were the

first two drugs where pharmacokinetics was studied. Mitomycin C became

the drug of choice for colorectal cancer. This drug has been challenged by

oxaliplatin

which has now become popular partly due to high concentra-

tions achieved IP and its success in the systemic treatment of CRC.

Table 2.1 – Comparison of HIPEC techniques as described by Glehen et al

.

The oxaliplatin treatment was combined in a bidirectional approach using 5- FU as an IV drug administered concurrently during surgery

. This treatment of colorectal cancer was further developed by adding irinotecan to the perfu- sion of the abdomen together with oxaliplatin

, which made the HIPEC treatment a triple drug treatment (5-FU IV, oxaliplatin and irinotecan IP).

Even though the triple drug treatment has gained popularity, there is no stan- dardisation as yet concerning the choice of drugs to be used. For colorectal cancer the two main drugs in current clinical practice are oxaliplatin or mi- tomycin C.

HIPEC is the dominant form of intraperitoneal chemotherapy, particularly in CRC. However, this is not the case with all tumour types, as SPIC treat- ments have shown progress in research with ovarian cancer

where SPIC is used more often than HIPEC.

Chemo-sensitivity testing

As previously mentioned, 5-FU (EPIC and SPIC), mitomycin C, and ox- aliplatin (HIPEC) are the main drugs used for the IPC treatment of colorectal PM. However, there are a number of new chemotherapeutic drug alterna- tives. One way to develop drug candidates for further investigation is through the chemo-sensitivity testing of tumours. There are a number of ways to study chemo-sensitivity. One method is clonogenic assays where the ability of cancer cells to form colonies after a few weeks of agar medium

Technique Advantages Disadvantages

Closed intra-

operative technique • Minimises exposure of OR staff to chemotherapy

• Easier to achieve high perfusion temperatures

• Increased drug penetration and tissue uptake with high intra- abdominal pressure

• Uneven heat distribution

• Lack of uniform drug distribution

Open intra- operative coliseum technique

• More uniform heat distribution

• More uniform drug distribution • Increased risk of OR staff exposure to chemother- apy

• Heat dissipation Peritoneal cavity

expander • Uniform distribution of chemo-

therapy • Increased risk of OR staff

exposure to chemother- apy

• More complex apparatus Semi-closed (semi-

opened) intra- operative technique

• More uniform heat distribution

• More uniform drug distribution

• Minimises exposure of OR staff to chemotherapy

• More complex apparatus

• Not in common use

culture can be evaluated.

Cell proliferation assays are another method for measuring the proliferative activity of cells over a few days.

At Uppsala University Hospital an updated, fully automated, 384-well method of the fluorometric microculture cytotoxicity assay (FMCA) has been developed and adapted to robotics. Applications of this method are similar to those used in the colorimetric MTT assay.

However, these two assays have different endpoints: the MTT assay measures cell metabolism, whereas the FMCA measures the esterase activity of cells with intact plasma membranes.

It does this by measuring the fluorescence generated when the non-fluorescent probe, fluorescein diacetate, is hydrolysed. The MTT assay and the FMCA yield similar results but the FMCA method is more sensitive. Furthermore, the preparation of drug plates and the use of a staining procedure without organic solvents make it an easier method to use.

Tumour samples from patients with all types of PM treated with CRS and IPC have routinely been analysed using the FMCA method for evaluating chemo-sensitivity to stan- dard and new experimental drugs with the hope that in the future this may assist the clinician in choosing an individually tailored chemotherapy regi- men for the patient.

2.5 The premises of the thesis

Over the past 10 years, research on the treatment of colorectal PM with CRS and IPC has grown considerably. Concerning HIPEC, there is one random- ised control trial

and two case-control trials

demonstrating a superior overall survival rate compared with systemic treatment alone. Concerning SPIC, there is one randomised and one case-control trial compared with sys- temic chemotherapy

. For EPIC, there is one comparative randomised trial with systemic treatment, but this failed due to recruitment problems.

These studies have been small with IPC treatment groups of fewer than 100 patients, but they all suggest superior efficacy of IPC treatment over sys- temic chemotherapy.

Although the comparative studies are rather small, a number of larger ob-

servational studies exist. A few multi-institutional studies have been con-

ducted: two French studies with 506 and 523 patients and one Italian study

with 146 patients

. Furthermore, two other studies have been published

with more than 100 patients

. All of these studies show the efficacy of

CRS and IPC in treating colorectal PM and many medical and surgical on-

cologists will refer patients for this treatment

. Despite this progress, some

contention remains concerning this treatment option for colorectal PM. In a

recent review article of CRS and IPC treatment for different tumour types,

the conclusion drawn concerning colorectal cancer was that more Phase III

randomised trials are needed

. There are several aspects of the CRS and IPC

treatment that contribute to the remaining scepticism.

Current research problems in the area of colorectal PM

The biggest challenge with the CRS and IPC treatment option for colorectal PM is that there is essentially only one small randomised control trial

. Since this trial, systemic treatment has gone through several advances that make the current validity of the comparison in this trial questionable. It would seem easy enough to conduct a new trial. However, this has turned out to be much more difficult than previously thought. One recent attempt at a randomised trial failed due to recruitment problems

. There are a number of observational trials showing quite significant long-term survival and this is what makes recruitment to a randomised trial difficult. Patients want the option that may cure them, instead of merely keeping the disease stabilised through systemic chemotherapy. This leaves the research community in a Catch 22 situation – more randomised trials are needed, but conducting these trials is probably not feasible. Despite this difficulty, there are several as- pects that may help to shed light on whether this treatment is a valid treat- ment option for colorectal PM.

The first aspect is the analysis of treatment outcome. Large cohort studies are a good way to show the efficacy of a treatment but the problem with many of the current cohort studies is that very few have reported the out- come of their open-and-close cases. In a randomised trial, these cases would still be included in the surgical arm and reported in the studies. This aspect of outcome analysis was addressed in Paper I. The open-and-close cases were included in Paper I as well as an outcome analysis of recurrences which is something few other studies have evaluated

.

A second aspect is that of patient selection. All agree that patients need to be in good physical health with the ability to combat adverse events and that their disease must be confined to the peritoneal cavity (with the possible exception of 1-3 liver metastases) and without retroperitoneal lymph node metastases

. Beyond this, there are no definite criteria for patient selec- tion. Some centres use neo-adjuvant chemotherapy response as a criterion (with little direct evidence)

. Other centres use laparoscopy to stage the di-

Table 2.2

sease extent because radiology is still unable to accurately evaluate the ex- tent of PM

. This issue is addressed in Paper II where the patient selection process was reviewed and a patient selection score based on tumour biology

Aspects investigated in this thesis

1. Treatment outcome analysis Paper I

2. Patient selection Paper II

3. Intraperitoneal chemotherapy

a. Method of administration (HIPEC vs. SPIC) b. What to administer (chemo-sensitivity)

Paper III

Paper IV

using serum tumour markers was developed in the hope that it can assist the surgeon in making well-founded decisions.

A third aspect is that of optimising the IPC (Table 2.2). There are several

areas of the IPC treatment that need to be evaluated clinically as mentioned

in section 2.4 “Intraperitoneal chemotherapy”. This thesis addresses two

areas, the method of administration and what to administer. Concerning

methodology, there are three ways of administering IPC – HIPEC, EPIC,

and SPIC. All have been proven more efficacious than systemic therapy in

the small comparative trials mentioned above. A comparison between

HIPEC and EPIC has shown HIPEC to be of greater value

. However, no

comparison between HIPEC and SPIC had been conducted and this was the

aim of Paper III. Concerning “what to administer” (Table 2.2), it is not fea-

sible to test all different possible combinations of drugs to arrive at the best

treatment as the patient base is rather small. It could, however, be interesting

to investigate ex vivo chemo-sensitivity profiles in order to choose the most

relevant drugs to evaluate in confirmatory clinical trials. This has already

been successful in leukaemia and to some extent in ovarian cancer

. In-

vestigating this aspect in an exploratory study for colorectal cancer was part

of the aim of Paper IV.

3 Aims of the thesis

The overall aim of the thesis was to investigate different aspects of the CRS and IPC treatment of colorectal PM in order to identify possible ways to optimise the treatment and to clarify its potential clinical usefulness. The following elements were investigated in the different studies: treatment out- come analysis, patient selection, method of administration (HIPEC vs.

SPIC), and chemo-sensitivity.

Specific aims:

I. Paper I

• To analyse the outcomes and prognostic variables of colo- rectal PM patients treated with CRS and IPC

• To analyse the outcomes after treatment of recurrences

II. Paper II

• To evaluate the exclusion and inclusion criteria basis for CRS and IPC by analysing the decision-making process

• To develop a scoring system based primarily on serum tumour markers (STMs) that could predict short cancer- specific survival

III. Paper III

• To compare two methods of IPC (HIPEC and SPIC) with respect to overall survival, disease-free survival, morbid- ity, and mortality

IV. Paper IV

• To investigate differences in chemo-sensitivity between various PM tumour types

• To investigate differences in clinical outcome depending

on chemo-sensitivity within the subset of colorectal can-

cer

4 Common methods

Ethical considerations

The regional ethics committee approved the studies and informed consent was obtained from each patient.

The CRS and IPC database and eligibility requirements

Data collection was performed using the CRS and IPC database at Uppsala University Hospital, Uppsala, Sweden. All patients who have received IPC treatment since 1996 are registered in this database and all patients from Papers I-IV were retrieved from this database. PM was determined either through surgical exploration, by radiology or by histopathology. The eligibil- ity requirements for the CRS and IPC programme are the following: no ex- tra-abdominal metastases, no aortic lymph node metastases or non-resectable liver metastases (>3 metastases); normal haematopoietic, liver and renal functions; and a WHO performance status of 0, 1 or 2.

The SPIC procedure

The SPIC patients received a PORT A CATH (No. 21-2000-04, SIMS Deltec, Inc., St Paul, MN, USA) placed subcutaneously above the periost of the lower ribs with the catheter tunnelled through the abdominal wall and directed towards the principal tumour site

. A SPIC treatment consisted of 5-fluorouracil 500-600mg/m

administered intraperitoneally and leucovorin 60mg/m

administered intravenously once a day for six days. Patients changed position during the infusion according to a set scheme so as to aid the dispersion of the chemotherapy in the abdomen. Eight cycles were planned during a 6-month period postoperatively.

The HIPEC procedure

The open coliseum method was used in this thesis, as previously described

.

Briefly, a Tenckhoff inflow catheter was placed centrally in the abdomen

and four outflow catheters were inserted through separate stab incisions

through the abdominal wall. Both the inflow and outflow catheters were

connected to a perfusion pump and a heat exchanger. The skin of the abdo- men was attached to a retractor ring and covered with a plastic film. A per- fusate circulation was established and after reaching the optimal temperature (approximately 42

C) a chemotherapeutic agent was administered. The tem- perature was monitored by three thermal probes placed in different areas of the abdomen during the perfusion. Different carrier fluids and chemotherapy agents were used in the different studies (see below). Before perfusion, the body temperature was lowered to 35

C with a cooling blanket (Allon 2001 Thermowrap, MTRE Advanced Technology Ltd., Yavne, Israel).

General Statistics

Descriptive data were presented in all studies with the use of tables where appropriate. When two groups were compared (Paper III), the statistical in- ferences between the groups were performed using the Pearson X

test for categorical variables and the two-sample student’s t-test for continuous vari- ables. When multiple groups were compared (Paper IV), one-way ANOVA with Tukey’s multiple comparison post hoc test of group means was used.

Cross resistance between drugs (Paper IV) was analysed by the Spearman Rank correlation and the slope of the regression line was calculated with the least squares method.

Prognostic evaluations of variables with survival as an endpoint were conducted by means of univariate and multivariable Cox regression analy- ses. Results were displayed as hazard ratios with 95% confidence intervals and p-values. The multivariable analyses were conducted including only statistically relevant variables from the univariate analyses. The p-level for this differed between the studies (p=0.05-0.1) depending on the size of the study or the stability of the data (see each respective Paper in the appendi- ces). An all-effects function was implemented using both forward and back- ward step-wise analysis. The statistics section of each respective paper in the appendices demonstrates how missing data was handled in these regression analyses. In all studies, post-operative deaths were considered censored data.

In Paper II, a quartile analysis of serum tumour markers was performed within the framework of a Cox regression model.

Survival analyses in the different studies were graphically represented ac- cording to the Kaplan-Meier method. When relevant, statistically inferred differences between two groups were determined using the log-rank test for large groups (e.g. Paper I) or Cox’s F test for small groups (e.g. Paper III).

The level of significance for all statistical tests (with some exceptions in the Cox regression analysis – see above) was set to p<0.05. The statistics soft- ware used was primarily STATISTICA 10.1 (StatSoft Inc, Tulsa, OK, USA);

and in Paper IV, GraphPad Prism Version 5 for Mac (GraphPad Software,

San Diego, CA, USA) was also used.

5 Summary of Papers

5.1 CRS and IPC treatment of colorectal PM

Paper I: Cytoreductive Surgery and Intraperitoneal Chemotherapy for Colorectal Peritoneal Carcinomatosis: Prognosis and Treatment of Recurrences in a Cohort Study

The first aspect investigated in this thesis is that of treatment outcome. Paper I investigated overall survival, disease-free survival, and prognostic factors after CRS and IPC treatment as well as survival after additional surgical treatments for recurrences.

Patients and methods

The study included all colorectal cancer patients who have undergone CRS and IPC since the program started in 1996. Study cohort inclusion ended at the end of 2010 and resulted in 151 patients. The eligibility requirements are specified above. A number of pre- and peri-operative prognostic factors were collected as well as 90-day morbidity and mortality. The 90-day treatment- related morbidity was reported according to the Common Terminology Cri- teria for Adverse Events v3.0 and only adverse events of grades III to V were registered.

The cytoreductive surgery (CRS) technique was mainly performed ac- cording to Sugarbaker (see section 2.3). Two intraperitoneal treatment tech- niques were in use during this time period: SPIC and HIPEC. The SPIC and HIPEC methods are described in detail in Chapter 4 (Common methods).

Chemotherapy regimens used during HIPEC treatment consisted of either a single drug treatment with mitomycin C 30-35mg/m

for 90 minutes and no IV chemotherapy (n=2), or bidirectional double drug treatment with ox- aliplatin 460mg/m

for 30 minutes IP combined with 5-FU 400mg/m

and calciumfolinate 60mg/ m

IV (n=44), or bidirectional triple drug treatment with oxaliplatin 360mg/m

and irinotecan 360mg/m

for 30 minutes IP com- bined with 5-FU 450-500mg/m

and calciumfolinate 60mg/ m

IV (n=23).

The chemotherapy regimen used during SPIC is detailed in chapter 4 (Com-

mon methods).

Follow-up data on recurrences, treatments of recurrences, postoperative systemic chemotherapy, date and cause of death were collected on all pa- tients as extensively as possible. All patients with recurrences were divided into three subgroups: isolated liver recurrences, isolated peritoneal recur- rences, and the remaining recurrences. Time to recurrence and choice of treatment data were collected on each patient. In the liver and peritoneal groups, the patients undergoing third-line surgical or invasive treatment were compared to those receiving best supportive care (with or without chemo- therapy depending on performance status) in terms of overall survival. The rest of the recurrences received palliative chemotherapy or best supportive care and the overall survival in this group was calculated.

Results

Out of 151 patients with colorectal cancer undergoing surgery for colorectal PM, 126 were treated with combined CRS and IPC (69 HIPEC and 57 SPIC), 23 were open and close cases, and two were treated with CRS with- out HIPEC or SPIC. Location and time of recurrences are displayed in Table 5.1. The Grade III-IV 90-day morbidity was 30% in the SPIC group and 41% in the HIPEC group (p=0.02). The 90-day, treatment-related mortality was 3% in the SPIC group and 4% in the HIPEC group (p=0.98). For spe- cific adverse events see Table 5.2.

Table 5.1 - Recurrences after cytoreductive surgery and intraperitoneal chemother- apy in colorectal peritoneal carcinomatosis

n=151

(%)

(range)

Median Survival in Months

Surgery grossly incomplete

No recurrences Isolated peritoneal Isolated liver Isolated lung

Both peritoneal and systemic Multiple systemic sites Isolated brain

Isolated testicle Missing data

41 (27.2%) 37 (24.5%) 20 (13.2%) 16 (10.6%) 10 (6.6%) 14 (9.3%) 3 (2.0%) 1 (0.7%) 1 (0.7%) 8 (5.3%)

0 N/A 10.7 (2.8-38) 7.5 (0.5-24) 5.4 (0.5-22) 6.7 (3-36) 4.9 (1-12) 2.0 (N/A) 33.0 (N/A)

N/A

6.7 Not reached

12.5 14.6 6.7 14.1 Not reached

11.6 Not reached

N/A

Survival and prognostic factors

In Figure 5.1, the median overall survival (OS) was 34 months (range: 2-77) for CRS and HIPEC with five-year survival predicted at 40%. For CRS and SPIC, the OS was 25 months (range: 2-188) with five-year survival at 18%.

Open-and-close patients survived 6 months (range: 0-14) with no five-year

survival (HIPEC vs. SPIC p=0.047, SPIC vs. open-and-close p<0.001). The

median survival of HIPEC patients with CC 0 was 39 months and for SPIC

patients with CC 0 it was 32 months (p=0.3). The disease-free survival (DFS) for HIPEC was 15 months and for SPIC 10 months (p=0.048) with a five-year DFS at 32% and 12%, respectively. Median OS for the entire co- hort was 24 months and five-year OS was 20% (five-year DFS 15%).

Table 5.2 - Postoperative morbidity in HIPEC (n=69) & SPIC treatment (n=57)

n=126

adverse events

(%)

Re-operation

within 90 days Mortality

Infections

Intra-abdominal infection Sepsis

Surgical

Enterocutaneous fistula Other intra-abdominal fistulas Wound dehiscence

Postoperative bleeding Anastomotic leak Urinary leak Intensive post-op pain Bile leak

Gastric perforation Bowel obstruction (surgical) Cardiovascular

Atrial fibrillation Cerebral vascular lesion Pulmonary embolism Deep vein thrombosis Arterial embolism (leg) Vena cava thrombosis Miscellaneous

Pleural effusion Kidney failure Liver failure

Haemolytic uraemic syndrome Bowel obstruction (tumour)

8 (6.3%) 8 (6.3%) 7 (5.6%) 2 (1.6%) 3 (2.4%) 3 (2.4%) 3 (2.4%) 2 (1.6%) 2 (1.6%) 1 (0.8%) 1 (0.8%) 1 (0.8%) 2 (1.6%) 2 (1.6%) 1 (0.8%) 1 (0.8%) 1 (0.8%) 1 (0.8%) 5 (4.0%) 1 (0.8%) 1 (0.8%) 1 (0.8%) 1 (0.8%)

3 2 2 1 1 1

1

1

1

1 1

a ^{58 (46%)* 10 (8%) 5 (4%)}

* Several patients had multiple Grades III-IV adverse events, which is why the percentage here is higher than what is presented in the text for HIPEC and SPIC individually.

PCI, CC score, type of IPC, white blood-cell count and adjuvant systemic

chemotherapy were independent prognostic factors in the multivariable

analysis for OS (Table 5.3). In patients with CC 0 score, PCI and adjuvant

chemotherapy were independent prognostic factors (Table 5.4). The median

time from primary surgery to CRS was 3 months in synchronous PM

(n=102) and 27 months in metachronous PM (n=48). The mean in-hospital

stay was 18 days while the mean operating time and bleeding was 440 min-

utes and 1,470 ml.

150 98 56 21 11 10 Total numbers at risk

Figure 5.1 - Survival according to HIPEC, SPIC, or open and close (n=150

)

a Overall survival data was missing in one patient, ^b HIPEC vs. SPIC p=0.047, SPIC vs. Open- and-close p<0.001. Abbreviations: HIPEC = Hyperthermic intraperitoneal chemotherapy, SPIC = sequential postoperative intraperitoneal chemotherapy

Analysis of liver and peritoneal recurrences

Patients with liver-specific interventions had a 35 month (range: 12-48) me- dian OS from the time of the third-line treatment and the palliative treatment group had a median OS of 12 months (range: 4-26, p=0.03). In the interven- tion group, the median time to the liver recurrence was 12 months and in the non-intervention group it was 5 months. There was no 90-day mortality.

The median time to the peritoneal recurrence was 12 months in the sur-

gery group and 7 months in the non-surgery group. The median survival of

the surgery group was 23 months (range: 9-98) and in the palliative treat-

ment group it was 6 months (range 1-26; p=0.007). Figure 5.2 displays an

overview of aggressive intervention vs. palliative care (systemic chemother-

apy or best supportive care) for both peritoneal and liver. Median OS in de-

tail was as follows: intervention vs. systemic chemotherapy (25 vs. 15

months, p=0.02), intervention vs. best supportive care (25 vs. 2 months,

p=0.03), and intervention vs. unknown palliative group (25 vs. 8 months,

p=0.01).

Table 5.3 and 5.4 - Prognostic analysis for overall survival in the cohort (Table 5.3) and in CC-0 patients (Table 5.4 details only significant variables)

Characteristic (n) Univariate Hazard Ratio

Univariate

p-value Multivariate p-value

General

Female gender (75) Age

Synch vs. metach (102 vs. 48) Histology

LN-positive vs. negative (95 vs. 29) Mucinous (89)

Signet-cell (18) Tumour grade Low (45) Intermediate (87) High (18)

Rectal vs. colon cancer (15 vs. 135) Laboratory results

Haemoglobin < 120g/L (56)

White blood cell count > 9x10

/L (32) Platelet count < 350x10

/L (38) Prognostic scores

PCI (as continuous variable) PCI I:1-10 (49) PCI II: 11-20 (45) PCI III: 21-39 (56) PSS 0 (19)

PSS 1 (29) PSS 2 (60) PSS 3 (42)

CC 1-3 vs. CC 0 (97 vs. 53) Tumour distribution according to PCI region 1-3.

No tumour present (63) Tumour in one region (20)

Tumour present multiple regions (67) Chemotherapy

Neoadjuvant chemotherapy (47) Adjuvant chemotherapy

(27) HIPEC vs. SPIC (69 vs. 57)

0.65 (0.43-0.98) 0.99 (0.98-1.00) 0.86 (0.56-1.32) 1.49 (0.83-2.68) 1.00 (0.66-1.51) 1.01 (0.54-1.91) 0.84 (0.44-1.63) 0.71 (0.39-1.32) Reference 1.12 (0.59-2.10) 1.17 (0.76-1.78) 1.71 (1.07-2.75) 1.72 (1.06-2.78) 1.05 (1.03-1.08) Reference 1.32 (0.76-2.31) 3.24 (1.95-5.39) 1.20 (0.54-2.66) 0.70 (0.36-1.40) 1.34 (0.81-2.23) Reference 5.51 (3.57-8.51)

0.30 (0.12-0.75) 0.44 (0.19-1.03) 2.49 (1.59-3.91) 1.14 (0.65-2.02) 0.27 (0.12-0.58) 0.60 (0.36-0.99)

0.04 0.19 0.50 0.67 0.98 0.97 0.99 0.25 0.73 0.47 0.01 0.03

<0.001 0.19

<0.001 0.18 0.06 0.19

<0.001

0.04 0.31 0.02 0.64

<0.001

<0.001

0.41

0.09 0.15 0.004

0.30

0.006

0.39 0.23

0.003 0.001 Table 5.4

Prognostic scores

PCI (as continuous variable) PCI I (1-10)

PCI II (11-20) PCI III (21-39) Chemotherapy

Adjuvant chemotherapy*

HIPEC vs. SPIC

1.03 (1.00-1.07) Reference 1.19 (0.59-2.41) 2.08 (0.95-4.53) 0.42 (0.18-1.00) 0.71 (0.37-1.34)

0.08 0.57 0.08 0.005

0.07

0.001

0.001 0.36

* missing data in 5 patients

Abbreviations: HIPEC = hyperthermic intraperitoneal chemotherapy, SPIC = sequential postoperative intraperitoneal chemotherapy, PCI = peritoneal cancer index, PSS = prior surgical score, CC = complete- ness of cytoreduction, Synch = synchronous, Metach = metachronous, LN = lymph node

37 18 7 3 3 1 Total numbers at risk

Figure 5.2 - Survival of additional invasive treatment of liver and peritoneal re- currences.

a For specifics within the palliative care group see the result section above. ^b Additional surgery or local intervention for both peritoneal and liver recurrences (p=0.01)

Discussion

This study includes the results of every patient that entered the operating room, including open-and-close patients. Despite this, the results from the whole cohort are quite impressive with a five-year overall survival (OS) of 20% and a disease-free survival (DFS) of 15%. This is better than any sys- temic chemotherapy treatment published to date, where typically there are few, if any, patients with a five-year DFS

. Narrowing in on the HIPEC patients, the five-year OS was 40% with a five-year DFS of 32%. Neverthe- less, the survival of the open-and-close patients is very poor with no five- year survivors and a median OS of 6 months. It is clear from this study that the patient selection process must be improved in such a way that the num- ber of open-and-close patients is reduced. This is the topic of Paper II and will be dealt with later. Furthermore, these results make randomised trials between CRS/IPC and systemic chemotherapy difficult and perhaps unethi- cal.

Concerning the prognostic analysis, an interesting variable was adjuvant

systemic chemotherapy. One earlier study showed that adjuvant systemic

chemotherapy after CRS and HIPEC is beneficial for overall survival

. The current study was able to confirm this prognostic benefit. However, it would be useful to perform a randomised trial before establishing a clinical routine with adjuvant systemic chemotherapy.

This study was the first to report the outcomes of additional liver surgery due to recurrences after prior CRS and IPC. Continuing an aggressive surgi- cal approach to isolated recurrences appears beneficial in selected patients.

As seen in Figure 5.2, the median survival of further interventional treat- ments of isolated liver or peritoneal recurrences was 25 months. Those pa- tients undergoing palliative chemotherapy had poor survival. However, the selection bias is an obvious confounder here, rendering the comparison moot. Even so, the survival rates, as such, are impressive, confirming that good results can still be achieved in selected patients with isolated liver or peritoneal recurrences. Therefore, prior CRS and IPC should not automati- cally preclude patients from further surgical or interventional treatment.

In conclusion, this cohort study shows that impressive OS and DFS can

be achieved in patients with colorectal PM following CRS and IPC and that

adjuvant chemotherapy might be beneficial. Randomised trials for colorectal

PM comparing CRS and IPC with systemic chemotherapy alone may not be

possible considering long term DFS. Furthermore previous CRS and IPC

should not automatically preclude patients from further surgical treatment

following isolated disease recurrences, as long term survival is still possible

in this population.

5.2 Patient selection for CRS and IPC

Paper II: Patient Selection for Cytoreductive Surgery in Colorectal Peritoneal Carcinomatosis using Serum Tumour Markers – an Observational Cohort Study

The second aspect investigated in this thesis is that of the patient selection process. The first aim was to review the decision-making process in patient selection from referral to the operating table and the second aim was to de- velop a patient selection score to aid in this process.

Figure 5.3 – Flowchart of Paper II

a Internal application of the score (training set), ^b External validation of the score (validation set)

Patients and methods

All patients referred for CRS and IPC treatment at Uppsala University Hos-

pital over a four year period between January 1

, 2005 and December 31

,

2008 were enrolled in the study (Figure 5.3). Those patients who did not

undergo surgical treatment were included in a non-surgery group where the

reason for this decision was reviewed (the first aim). All others who under-

went surgery were enrolled in the surgery group (Figure 5.3). All patients in

the surgery group fulfilled the general eligibility criteria as mentioned in Chapter 4.

The second aim of developing a prognostic score in the surgery group was investigated by collecting from the database five STMs (CEA, CA 125, CA 19-9, CA 15-3, and CA 72-4) and haematological status [haemoglobin level (Hb), white blood cell count (WBC), and platelet count (PLT)] that are taken routinely two or three days prior to surgery on all patients undergoing CRS and IPC. Further data collected on patients undergoing CRS and IPC were date and cause of death, histopathology, peritoneal cancer index (PCI), prior surgical score (PSS), completeness of cytoreduction (CC), and the use of neo-adjuvant chemotherapy. PSS, PCI, and CC scores were quantified intra-operatively as described earlier in section 2.3.

In June 2006, the routine pre-operative workup for the CRS and IPC pa- tients was updated to include referral tests taken 2-3 months prior to surgery.

The 5 STMs (see above) were measured 2-3 months pre-operatively (referral tests) and 2-3 days pre-operatively (surgery tests). Changes in STM levels between the two tests were defined according to Table 5.5.

From Table 5.6 and 5.7, nine significant variables were selected to be in- cluded in the colorectal PM (Corep) score: Signet-cells, Hb, WBC, CEA, CA 125, CA 19-9, CA 15-3 plus response to chemotherapy (normal/regression vs. progression). The quartile analysis of the STMs was used to define cut- off points where statistically significant changes occurred. After these points were determined (see the results section), the hazard ratio for each variable was rounded off to the nearest whole number. These whole numbers were divided by two, and the resulting numbers were assigned as points for each variable in the Corep score (Table 5.8).

Table 5.5 – How STM changes were defined in the subgroup analysis.

Groups Description

– a change in tumour marker is defined as +/- 50% of the value 1 The markers were never elevated during the entire observation period.

2 Regression in at least 50% of the pathological tumour markers. If there is an even number of pathological markers, the other markers must not be defined as progressing.

3 Stabile disease or mixed response – those not defined in group 2 or 4.

4 Progression in at least 50% of the pathological tumour markers. If there is an even number of pathological markers

the other markers must not be defined as regressing.

The Corep score was developed in the training set of patients mentioned

above (n=35) and validated in an external set of 24 consecutively treated

colorectal PM patients treated with CRS and IPC (including open-and-close

cases) between 2009 and 2010 (Figure 5.4). Date and cause of death and CC

score were collected as well as the nine variables (Table 5.8) needed to vali-

date the score. The sensitivity, specificity, positive predictive value (PPV) and negative predicted value (NPV) for a Corep score ≥ 6 was calculated in terms of predicting short cancer-specific overall survival which was defined as survival <12 months. Censored cases before 12 months were not included in this calculation.

Results

Non-surgery group

Forty-two patients, colonic cancer patients only, did not proceed to surgery.

There were 16 male patients (38%) and the mean age was 59.4 years. In 24 patients (57%), the cause for denial of surgery was metastatic disease found during the pre-operative workup – 11 pulmonary, 8 para-aortal lymph node, 3 liver, and 2 thoracic lymph node metastases. Seven patients (17%) were excluded due to poor performance status or major clinical symptoms of in- testinal obstruction. Four patients (10%) refused surgery. Two patients (5%) were excluded on the basis of radiological PM findings indicating that the disease was too extensive. Both patients had extensive PM growth: one pa- tient also had an affected common bile duct and the other patient had vena cava growth subhepatically. Two patients (5%) failed down-staging of para- aortal lymph nodes with neo-adjuvant chemotherapy, two patients (5%) died of other causes prior to surgery, and in one patient (2%) data were missing.

Surgery group and prognostic score development

Paper II in the appendix presents a thorough description of patient character-

istics in the surgery group. The results of the univariate and multivariate Cox

proportional analyses are outlined in Tables 5.6 and 5.7. Nine variables were

eligible for the Corep score (Table 5.8). The hazard ratios (Table 5.6 and

5.7) of five variables (Signet cells, Hb, WBC, normal/regression in STMs,

and progression of STMs) were rounded off to whole numbers and trans-

ferred to Table 5.8. Cut-off points were defined at points where statistically

significant changes occurred (Table 5.6). These points were defined at

70µg/l for CEA, 350kU/l for CA 125, 70kU/l for CA 19-9, and 50kU/l for

CA 15-3. Hazard ratios from the quartile analysis were recalculated where

appropriate and rounded off to the nearest integer and transferred to Table

5.8. These rounded hazard ratios were then divided by two and used in the

Corep score.